Cutaneous T-cell lymphoma (CTCL) is a malignancy of the T-helper (CD4+) cells of the immune system. CTCL, also known as mycosis fungoides (MF), is a cancer of the white blood cells that primarily affects the skin and only secondarily affects other sites. This disease involves the uncontrolled proliferation of T-lymphocytes known as T-helper cells, so named because of their role in the immune response. T-helper cells are characterized by the presence of a protein receptor on their surface called CD4. Accordingly, T-helper cells are said to be CD4+.
The proliferation of T-helper cells results in the penetration, or infiltration, of these abnormal cells into the epidermal layer of the skin. The skin reacts with slightly scaling lesions that itch, although the sites of greatest infiltration do not necessarily correspond to the sites of the lesions. The lesions are most often located on the trunk, but can be present on any part of the body. In the most common course of the disease, the patchy lesions progress to palpable plaques that are deeper red and have more defined edges. As the disease worsens, skin tumors develop that are often mushroom-shaped, hence the name mycosis fungoides. Finally, the cancer progresses to extracutaneous involvement, often in the lymph nodes or the viscera.
CTCL is a rare disease, with an annual incidence of about 0.29 cases per 100,000 persons in the United States. It is about half as common in Eastern Europe. However, this discrepancy may be attributed to a differing physician awareness of the disease rather than a true difference in occurrence. In the Unites States, there are about 500-600 new cases a year and about 100-200 deaths. CTCL is usually seen in older adults; the median age at diagnosis is 55-60 years. It strikes twice as many men as women. The average life expectancy at diagnosis is 7-10 years, even without treatment.
The most common side effect for treatments applied to the skin is skin hypersensitivity to the drug. There is a need for improved compositions and methods for skin diseases that avoid or minimize skin hypersensitivity to the drug.